Explanation:
What are those unusual plates on Mars?
A leading current interpretation holds that they are
blocks of ice floating on a recently frozen sea covered by dust.
The unusual plates were photographed recently by the
European Space Agency's
Mars Express spacecraft currently orbiting
Mars.
Oddly, the region lies near the
Martian equator
and not near either of Mars'
frozen polar caps.
Without being covered by dust, any water or ice near away from the poles would quickly
evaporate right into the
atmosphere.
Evidence that the above-imaged plates really are dust-covered
water-ice includes a similarity in appearance to
ice blocks off Earth's Antarctica,
nearby surface fractures from which underground water could have flowed,
and the shallow depth of the
craters indicating that something is filling them in.
If correct, the low abundance of craters indicates
that water may have flowed on
Mars
as recently as five million years ago.